Stabilization of hydrocarbon lubricating oils, greases and fuels



United States Patent 3,399,041 STABILIZATION OF HYDROCARBON LUBRICAT. ING OILS, GREASES AND FUELS Leo J. McCabe, Glassboro, N.J., assignor to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Jan. 21, 1966, Ser. No. 522,044 8 Claims. (Cl. 4473) This invention relates to improved organic compositions and, in one of itsaspects, relates more particularly to improved organic compositions in the form of liquid and solid hydrocarbons that are normally susceptible to deterioration by corrosion or oxidation. Still more particularly, in this aspect, the invention relates to improved organic compositions in the form petroleum distillate hydrocarbon fuels, lubricating oils and greases which, in their uninhibited state, tend to react with and corrode metal surfaces with which they may come into contact in performing their intended functions.

It is well known that certain types of organic compounds are normally susceptible to deterioration by oxidation or by corrosion when coming into contact with various metal surfaces. For example, it is known that liquid hydrocarbons in the form of fuels or lubricating oils tend to accumulate considerable quantities of water when main tained for longperiods of time in storage vessels; and when subsequently brought into contact with metal surfaces in their functional environments, deterioration of equipment as a result of corrosion, occurs. As a further example, in modern internal combustion engines and in turbojet engines, lubricants can be attacked by oxygen or air at high temperatures to form heavy viscous sludges, varnish and resins which become deposited on the engine surfaces and acids corrosive enough to destroy metal. As a result, the lubricant cannot perform its required task efi'ectively, and the engine does not operate eificiently. In addition, where such lubricating oils or other corrosioninducing materials are incorporated into solid lubricants as in the form of greases, similar deleterious results are encountered, thus clearly indicating the necessity for incorporating into such organic compositions an effective antioxidant and rust-inhibiting agent. Increasing demands on lubricants, brought about by newer and larger engines operating at higher temperatures and pressures, necessitate the search for newer additives which can provide increased oxidation resistance.

Accordingly, it is an object of this invention to provide organic compositions having improved antioxidant and anti-corrosion properties.

Another object of the invention is to provide improved organic compositions in the form of liquid and solid hydrocarbons containing an additive which is adapted to prevent corrosion and oxidative deterioration of metallic surfaces. 7

Still another object of the invention is to provide an elfective antioxidant and corrosion inhibiting agent, and a method for its manufacture, for incorporation into the aforementioned organic compositions.

In general, the present invention, in its preferred'applications, contemplates organic compositions in which the aforementioned diaminodithiaalkanes function as antioxidants, anti-rust agents and metal deactivators for gasolines. Furthermore, they are also elfective as anti-rust agents and sediment stabilizers for various types of fuel oils; In organic compositions, generally, which are susceptible to the above-described forms of deterioration, small amounts of the diaminodithiaalkanes, usually from about .001 to about 10 percent, by weight, of the total of such composition, are effective. More specifically, when the diaminodithiaalkane is incorporated into liquid hydrocarbon fuels such as jet fuels, turbine fuels, gasolines and the like, or in lubricating oils, they are generally employed in an amount from about .001 to about .01 percent, by weight, of the total composition. When the diaminodithiaalkanes are incorporated into hydrocarbon grease compositions, they are preferably employed in an amount from about 0.1 to about 5 percent, by weight, of the total grease. In addition, as more fully hereinafter described, the aforementioned diaminodithiaalkanes may also be incorporated in the aforementioned organic compositions, in the ranges described, in the form of their bis-salicylaldimine derivatives.

The organic compounds improved in accordance with the present invention may comprise any materials that are normally susceptible to deterioration by oxidation or corrosion, in the manner previously described. A field of specific applicability is the improvement of liquid hydrocarbons in accordance with the present invention, boiling from about 75 F. to about 750 F. Of particular significance is the treatment of petroleum distillate fuels having an initial boiling point from about 75 F. to about 135 F. and an end boiling point from about 250 F. to about 750 F. It should be noted, in this respect, that the term distillate fuels is not intended to be restricted to straightrun distillate fractions. These distillate fuels can be straight-run distillate fuels, catalytically or thermally cracked (including hydrocracked) distillate fuels, or mixtures of straight-run distillate fuels, naphthas and the like, with cracked distillate stocks. Moreover, such fuels can be treated in accordance with well-known commercial methods, such as acid or caustic treatment, hydrogenattion, solvent-refining, clay treatment, and the like.

The distillate fuels are characterized by their relatively low viscosity, pour point and the like. The principal property which characterizes these contemplated hydrocarbons, however, is their distillation range. As hereinbefore Other objects and advantages inherent in the invention will become apparent to those skilled in the art from the following more detailed description.

It has now been found that the aforementioned oxidative and corrosive properties of organic compositions, particularly in the form of fuels and lubricants, can be effectively overcome by incorporating therein small amounts of a diaminodithiaalkane having the formula:

wherein R is selected from the indicated, this range will lie between about F. and about 750 F. Obviously, the distillation range of each individual fuel will cover a narrower boiling range, falling, nevertheless, Within the above-specified limits. Likewise, each fuel will boil substantially, continuously, throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2 and 3 fuel oils, used in heating and as Diesel fuel oils, gasoline and the jet combustion fuels, as previously indicated. The domestic fuel oils generally conform to the specifications set forth in ASTM Specification D396-48T. Specifications for Diesel fuels are defined in ASTM Specification D975-48T. Typical jet fuels are defined in Military Specification MIL-F-56'24B. In addition, as previously indicated, hydrocarbon lubricating oils of varying viscosity and pour points, falling both within and outside the indicated ranges for the aforementioned fuel oils, and synthetic oils may also be elfectively treated through the use of the aforementioned diaminodithiaalkanes or their bis-salicylaldimine derivatives, as antoxidation and anticorrosion agents.

As previously indicated, the aforementioned diaminodithiaalkancs or their bis-salicylaldimine derivatives may also be incorporated, as anti-corrosion agents, in grease compositions. Such greases, may comprise a combination of a wide variety of lubricating vehicles and thickening or gelling agents. Thus, greases in which the aforementioned diaminodithiaalkanes or their bis-salicylaldimine derivatives are particularly effective, may comprise any of the conventional hydrocarbon oils of lubricating viscosity, as the oil vehicle, and may include mineral or synthetic lubricating oils, aliphatic phosphates, esters and di-esters, silicates, siloxanes and oxalkyl ethers and esters. Mineral lubricating oils, employed as the lubricating vehicle, may be of any suitable lubricating viscosity range from about 45 SSU at 100 F. to about 6,000 SSU at 100 F., and, preferably, from about 50 to about 250 SSU at 210 F. These oils may have viscosity indexes varying from below to about 100 or higher. Viscosity indexes from about 70 to about 95 are preferred. The average molecular weights of these oils may range from about 250 to about 800. The lubricating oil is employed in the grease composition in an amount sufficient to constitute the balance of the total grease composition, after accounting for the desired quantity of the thickening agent, and other additive components to be included in the grease formulation.

As previously indicated, the oil vehicles employed in the novel grease formulations of the present invention, in which the aforementioned diaminodithiaalkanes or their bis-salicylaldimine derivatives are incorporated as antioxidative or anti-corrosion agents, may comprise mineral or synthetic oils of lubricating viscosity. When high temperature stability is not a requirement of the finished grease, mineral oils having a viscosity of at least 40 SSU at 100 F., and particularly those falling within the range from about 60 SSU to about 6,000 SSU at 100 F. may be employed. In instances, where synthetic vehicles are employed rather than mineral oils, or in combination therewith, as the lubricating vehicle, various compounds of this type may be successfully utilized. Typical synthetic vehicles include: polypropylene, polypropylene glycol, trimethylol propane esters, neopentyl and pentaerythritol esters, di-(2-ethyl hexyl) sebacate, di-(Z-ethyl hexyl) adipate, di-butyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chaintype polyphenyls, siloxanes and silicones (poly-siloxanes), alkyl-substituted diphenyl ethers typified by a butyl-substituted bis (p-phenoxy phenyl) ether, phenoxy phenyl ethers etc.

The lubricating vehicles of the aforementioned improved greases of the present invention containing the above-described diaminodithiaalkanes or their bis-salicylaldimine derivatives as additives, are combined with a grease-forming quantity of a thickening agent. For this purpose, a wide variety of materials may be employed. These thickening or gelling agents may include any of the conventional metal salts or soaps, which are dispersed in the lubricating vehicle in grease-forming quantities, in such degree as to impart to the resulting grease composition, the desired consistency. Other thickening agents that may be employed in the grease formation may comprise the non-soap thickeners, such as surface-modified clays and silicas, aryl ureas, calcium complexes and similar materials. In general, grease thickeners may be employed which do not melt and dissolve when used at the required temperature within a particular environment; however, in all other respects, any material which is normally employed for thickening or gelling hydrocarbon fluids for forming grease can be used in preparing the aforementioned improved grease in accordance with the present invention.

The diaminodithiaalkanes employed as additives for the organic compositions of the present invention, are prepared, in general, as more fully hereinafter described, by reacting two moles of an aziridine with one mole of ethane dithiol to obtain the corresponding diaminidithiaalkane having the general formula:

wherein R is selected from the group consisting of alkyl and hydrogen. This reaction is, in general, carried out at a temperature from about 0 C. toabout 150 C. and, preferably, at a temperature from about 30 C. to about C. When the aforementioned bis-salicylaldimine derivative is desired to be obtained, this compound is produced by reacting one mole of the above-described diaminodithiaalkane with two moles of salicylaldehyde. This latter reaction is, in general, carried out at a temperature from about 50 C. to about 150 C. and, preferably, at a temperature from about C. to about C.

The aforementioned reaction of the aziridine with ethane dithiol is represented by the following equation:

R CH Insofar as the aziridine reactant in the above formulas is concerned, it should be noted that any aziridine may be employed for this purpose. Preferred aziridines are:

ethylenimine propylene imine and butyleno imino C H C IIr-C H-'C II;

The following examples will serve to illustrate the preparation of the diaminodithiaalkanes, and their bissalicylaldimine derivatives, of the present invention and the method for their preparation. These examples will also serve to demonstrate the effectiveness of the aforementioned compounds in organic compositions which are normally susceptible to deterioration by oxidation, or corrosion, and particularly with respect to their use in hydrocarbon fuels. It will be understood, of course, that it is not intended that the invention be limited to the particular compositions shown or to the operations or manipulations involved. Various modifications thereof, as previously described, can be employed and will be readily apparent to those skilled in the art.

-Example l.Preparation of 1,8-diamino-3,6- with Example 3, in 150 ml. of benzene at 50 C. After vdithiaoctane the addition had been completed, the resulting mixture 200 m1 of dry benzene and 23 5 grams (0.25 moles) was refluxed and water formed was collected in a Barrett trap. After three hours a total of 8 ml. of water had of ethane dithlol werechar ed to a l-hter flask. The System' was kept moistureirgee and the flask contents 5 been collected; theory, 9.0 ml. The resulting product was then solvent-stripped to 125 C. under house vacuum were stirred and heated to a temperature of 40 C. Thereafter, 21.5 grams (0.5 moles) of ethylenimine was added 8 a ifg' f ig. gggfi az dropwise. The reaction was slightly exothermic. After rown syrup eana ysls 0 C s the addition had been completed, the resulting mixture fig g 67%; 154% Found: 17%; was heated at a temperature of 50-55 C. for a period 10 In order to determine the storage stability charactergf T13232 g iz iggiggg z? 381 igg i gg zg istics of the fuels in which the novel addition agents of vacuum. The yield was 39.5 grams (100%). The analysis the piesent mvennon i g g 3 .1 9 of this product calculated for C H N S was N 15.5 Gasoline Test was i oye n t test a 1 1 er S 35 6% Found N 14 2 2 15 sample of the gasoline under test is placed in a closed bottle and maintained at 110 F. for a period of 16 1 weeks. The bottles are sampled and aerated at approx1- Examp e 2 ziggg gigf gg mate 4 week intervals. Correlation stud1es have demonstrated that gum build-up in 16 weeks of this test corregrams a sponds to that developed during one to two years of P p 111 accordance Wlth Example 150 field storage. The existent gum was determined by the ml. of benzene, was added slowly to a solution of 51.2 ASTM Exi tent Gum Test 331) grams 0f salicylaldehyde ill 50 of A gasoline induction period test (ASTM D525) was Zelle- The resulting mixture was refluxed, and the water employed for these additives. In general, an increase in formed was removed y a Barrett P- A total of 8 I111- induction period reflects increased storage stability.

of water was Collected y, Teslllting The addition agents were also tested in gasoline con- Prodllct was Solvent-Stripped 011 a Iotavac to a p taining 0.2 mg./liter copper napthenate to evaluate the ture of 100 C. under house vacuum. A syrup was obddi i a et l deactivators. tained which crystallized upon standing overnight. The Th additi e f Examples 1 through 4 were indicfystallized Product was Y y grams vidually blended in a gasoline blend and were compared The recrystallized material had a melting point of 109- with the uninhibited base gasoline, with the results shown the analysis of this product calculated for in Table I. The data indicate that the addition agents C H N 0 S was: N, 7.2% S, 16.5%. Found: N, markedly improve the storage stability of the base fuel 6.9%; S, 17.0%. 1 in the absence and presence of added copper ion.

TABLE I.GASOLINE STORAGE TEST [Additive blended in a gasoline blend comprising 100% catalytically cracked component and boiling within the range from approximately 100 F.

to approximately 400 F.]

Add t ASTM 16 weeks at lliigoF. A gum, With 0.2 mgJl. copper naphthenate 1 we mg. m. Additive cone, induction ASTM 16 Weeks at 110 F. A gum,

lb/M bbl. period, mm. Residue Existent induction mg./100 ml.

period, min. Residue Existent 0 382 14. 7 11.2 161 41. 5 23. 2 1. o 463 8. 0 4. 0 478 13. 8 10. 8 D t8 2% it it 13% o 4 Gasoline blend 0 664 5. 8 4. 6 263 20. 7 16. 6 Gaslgine blend Plus Ex g 3. 7 610 21. 9 261.:

o 3.6 714 7.0 Gasoline blend 0 382 14. 7 11. 2 161 41. 5 23. 2 Gasoline blend Plus Ex. 2 1.0 488 6. 6 3.0 457 11.8 8. 4

s 1'8 23? at o s Gasoline blend 0 664 5. 8 4. 6 263 20. 7 16. 6 Gasizgine blend Plus Ex Z6; g 2% 20. 3

o 5 1. 1. 5 Gasoline blend 0 502 12. 5 11.0 258 38.0 25. 3

Example 3.Preparation of 2,9-diamino-4,7- As is apparent from the data in Table I, the addition dithiadecane 1 agents of the present invention are elfective in reducing A solution of 50.4 grams (0.88 moles) of inhibitor formation. m gaisolme F Storage There also free propylene imine was added dropwise to a stirred 0 an 99 i l penod for mmamlfig h Solution of 27 5 grams (0 44 moles) of ethane dithiol additives, mdlcatlng increased gasolme storage stab1l1ty 1n at 40 C. The first addition of the amine turned the the Presence of the addmon i i flask contents from yellow to pink. The reaction was In order.to.evaluate the addmves of the present Invari- Sli htl exothermic After the addition had been tron as antloxrdants for hydrocarbons and for ester lubni reaction'mixture was stirred at C for cants, these additives were subjected to a catalytic Oxidap g of two hours The Iesulting product was tion Test. Thls test determines the effectiveness of an addi- Stri ed to C under house vacuum using a rotavac tive in preventing the catalytic oxidation of the oil sample A 2 m was ob'tained The analysis calculated for under oxidizing conditions. The test procedure is as folzg g N Found. N, 12'7% lows: in a 200 mm. x 25 mm. test tube is placed a 25 gram sample of a test oil, having immersed therein (a) Example of zg'bls(sahcyhdeneamme' 15.6 sq. in. of sand-blasted iron wire, (b) 0.78 sq. in. of dlthladecane) polished copper wire, (c) 0.87 sq. in. of polished alumi- 61.0 grams (0.5 moles) of salicylaldehyde in 60 ml. num wire and (d) 0.167 sq. in. of a polished lead speciof benzene was added to 52.0 grams (0.25 moles) of men. In Test A the oil sample is heated to a temperature 2,9-diamino-4,7-dithiadeeane, prepared in accordance of 425 F. and maintained at this temperature while dry air is placed therethrough at the rate of liters per hour for a period of 24 hours. In Test B the temperature is maintained at 325 F., for a period of 40 hours. The change in neutralization number and kinematic viscosity before and after the oxidation are recorded, and the weight loss of the lead specimen is obtained. In Table II are shown the etfects of the additives of Examples 2 and 4 of the present invention, compared with the uninhibited lubricants.

For Test A the lubricant material employed was an ester mixture prepared from technical grade pentaerythritol and a mixture of C and C monocarboxylic acids.

For Test B a solvent refined Mid-Continent mineral oil was used.

8 wherein R is selected from the group consisting of alkyl and hydrogen.

2. A composition in accordance with claim 1, wherein said bis-salicylaldimine derivative of said diaminodithiaalkane is present in an amount from about .001 to about 10 percent, by weight, of the total of said composition.

3. A composition in accordance with claim 1, wherein said bis-salicylaldimine derivative of said diaminodithiaalkane is present in an amount from about .001 to about .01 percent, by weight, of the total of said composition.

4. A composition in accordance with claim 1 wherein said bis-salicylaldimine derivative of said diaminodithia- TABLE II.--EVALUATION OF BIS-SALICYLIDENDITI-IIADIMINE ADDITIVES IN CATALYTIC OXIDATION TESTS Additive Cone, wt. Initial NN ANN Initial KV Vis. Incr., Lead Loss,

percent (cs.) percent mg.

Test A 1 Base Lubricant 6. 6 26. 61 205. 0 15. 2 Base Lubricant plus Ex. 2 4. 0 1. 7 28. 20. 2 0 0 2.0 1.8 23.7 0.3 1. 0 2. 6 59. 7 0. 7 4. 0 1. 2 29. 39 15. 2 0. 3 2. 0 L 6 7. 0 0 1.0 2.0 20. 2 0. 9

Test B 3 Base Lubricant 0. 05 6. 5 22. 53 32. 5 20. 8 Base Lubricant plus Ex. 2. 0.32 1. 1 22.34 12. 0 0.8 Base Lubricant plus Ex. 4. 0.21 1. 3 22.30 22. 9 0. 7

1 KV=100 F. 3 KV=210 F.

As is apparent from the data in Table II the addition agents of the present invention are effective as antioxidants for synthetic ester lubricants (Test A) and also for hydrocarbon lubricants (Test B).

From the foregoing, it will be apparent that the diaminodithiaalkanes of the present invention, are markedly effective as antioxidants, anti-rust agents, metal deactivators and sediment stabilizers for organic compositions, and particularly with respect to gasolines and fuel oils, and more specifically, to the treatment of such hydrocarbons as petroleum distillate fuels, and also as elfective stabilizers for hydrocarbon and synthetic lubricants.

Although the present invention has been described with preferred embodiments, it will be understood that modifications and variations thereof may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand.

I claim:

1. Organic compositions normally susceptible to deterioration, selected from the group consisting of hydrocarbon lubricant oils and greases and liquid hydrocarbon fuels, containing a small amount sufficient to inhibit said deterioration, of the bis-salicylaldimine derivative of a diaminodithiaalkane, having the formula:

alkane is present in an amount from about 0.1 to about 5 percent, by weight, of the total of said composition.

5. A composition in accordance with claim 1 wherein said composition is a liquid hydrocarbon fuel comprising a petroleum distillate fuel oil having an initial boiling point from about F. to about F. and an end boiling point from about 250 F. to about 750 F.

6. The composition of claim 1 wherein said liquid hydrocarbon fuel comprises a gasoline.

7. The composition of claim 1 wherein said liquid hydrocarbon fuel comprises a jet fuel.

8. The composition of claim 1 wherein said liquid hydrocarbon fuel comprises a turbine fuel.

References Cited UNITED STATES PATENTS 2,282,513 5/1942 Downing et a1. 4473 2,282,710 5/1942 Dietrich 25247 2,304,623 12/1942 Berchet 25247 2,626,208 1/ 1953 Brown 4473 FOREIGN PATENTS 633,543 12/ 1961 Canada.

DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,399,041 August 27, 1968 Leo J. McCabe It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 35, in the formula, should read +2 Column 5, line 17, "salicylideneamine" should read salicylideneamino line 70, "salicylideneamine" should read Column 6, line 23, after "was" salicylideneamino 4,7- insert also Column 7, lines 59 to 61,

portion of the formula reading the righthand I CHNH should read CHNH2 Signed and sealed this'lISth day of January 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Attesting Officer 

1. ORGANIC COMPOSITIONS NORMALLY SUSCEPTIBLE TO DETERIORATION, SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON LUBRICANT OILS AND GREASES AND LIQUID HYDROCARBON FUELS, CONTAINING A SMALL AMOUNT SUFFICIENT TO INHIBIT SAID DETERIORATION, OF THE BIS-SALICYLALDIMINE DERIVATIVE OF A DIAMINODITHIAALKANE, HAVING THE FORMULA:
 5. A COMPOSITION IN ACCORDANCE WITH CLAIM 1 WHEREIN SAID COMPOSITION IS A LIQUID HYDROCARBON FUEL COMPRISING A PETROLEUM DISTILLATE FUEL OIL HAVING AN INITIAL BOILING POINT FROM ABOUT 75*F. TO ABOUT 135*F. AND AN END BOILING POINT FROM ABOUT 250*F. TO ABOUT 750*F. 